Panoply™ Human AOC3 Knockdown Stable Cell Line

Here, researchers employed advanced next-generation sequencing (NGS) and bioinformatics strategies to analyze normal and cancerous tissues from lung cancer patients. Amine oxidases are closely associated with leukocyte migration and tumorigenesis. However, the mechanism of action of amine oxidases in lung cancer remains unclear. These results indicate that, compared to normal tissues, the mRNA and protein levels of amine oxidase copper containing 3 (AOC3) were significantly reduced in tumor tissues from included lung cancer patients and in public databases. Low AOC3 expression was associated with decreased patient survival in different cohorts. miR-3691-5p-mediated AOC3 epigenetic silencing promotes tumorigenesis and development through enhanced cell migration and epithelial-mesenchymal transition (EMT). Furthermore, in vitro experiments showed that knocking down AOC3 reduced CD4+ T cell adhesion and transendothelial migration to lung cancer cells, while in vivo experiments also showed that AOC3 reduced CD4+ T cell migration to the lungs. In summary, these studies reveal that downregulation of AOC3 expression mediates lung cancer development and leads to reduced immune cell recruitment. This discovery helps to better understand the dysregulation mechanisms of the tumor immune microenvironment and may provide new strategies for lung cancer treatment.

Low AOC3 expression is associated with poor prognosis in lung cancer patients. Therefore, researchers investigated the mechanism by which AOC3 mediates lung cancer progression. They constructed an AOC3-knockdown LUAD cell line with a knockdown efficiency exceeding 50% (Figure 1A). Subsequently, the effect of AOC3 knockdown on cell proliferation was investigated. Both WST-1 and BrdU assays showed that AOC3 did not affect lung cancer cell proliferation (Figures 1B and 1C). Cell migration was assessed using a scratch wound healing assay, which showed enhanced cell healing ability (enhanced migration) after AOC3 knockdown (Figure 1D). Furthermore, mesenchymal characteristics were enhanced in AOC3-knockdown cells, manifested by increased expression of N-cadherin, vimentin, and Slug proteins (Figure 1E). The researchers added recombinant human AOC3 protein (rhAOC3) to validate the observed changes in cell proliferation and migration. Even at a high dose (50 ng/ml) of rhAOC3 treatment, cell proliferation remained unchanged, as confirmed by WST-1 and BrdU assays (Figures 1F and 1G). Wound healing experiments showed that the addition of rhAOC3 reduced cell migration capacity in a dose-dependent manner (Figure 1H). With increased E-cadherin expression, N-cadherin, vimentin, and Slug expression decreased, and mesenchymal cell characteristics transitioned to epithelial cell characteristics in a dose-dependent manner (Figure 1I). These results indicate that decreased AOC3 expression plays a role in lung cancer progression by promoting cell migration and EMT (epithelial-mesenchymal transition) rather than inhibiting cell proliferation.

Figure 1. AOC3 mediates EMT in lung cancer. (Chang C Y, et al., 2021)